Dental flask



Sept. 12, 1933. c. s. BALLARD 1,926,508

DENTAL FLASK Filed March 25, 1933 2 Sheets-Sweet 1 INVENTOR ATTORNEYS Sept. 12, 1933. c s BALLARD 1,926,508

DENTAL FLASK Filed March 25, 1953 2 Sheets-Sheet 2 INVENTOR ATTORNEYS engagement with a recess '38; in pin 22. )As a further convenience, latch32 is provided with a normally downwardly extending handle portion 38 which in addition to serving as a handle tor the retraction of latch 32, which could'be grasped;

and pulled directly outwardly may -also:act as v a cam follower; I find itdesirable to employ an as awhole. i I H The two-'; portions of tliednterlirierare valso provided with male and-femalecentering and se- I f curing means as 'the male portionsetand the fe-' "male guide 66 which they engage respectively.

inserted annular cam member '40,"arranged' in such a manner that as handle '38 is revolved upwardly it engages cam 40 to-withdraw latch. 32

from recess 33 and when it is fully withdrawn it is adapted to rest in the locking notch or slot.

42 formed in the surface of cam 40. I

Cover plate 16 is'provided with a plurality of,

holes 44 which serve as aconvenientescape means for surplus plasten II Adapted to seat within the flask arethe two companion flask interlining members 46 and 48.' I Thesev'are of-sucl'ra %size that they willeasily go into theinterior of the flask and be spaced somewhat-fromfitiexcepton, the medial plane where outstanding lipswhich are ofnecessity provided for resting and spacing the flask members. Thus the interliners 46 and 48are adapted -to engage a members 10 and-"12 respectively and be' centered and spaced therefrom by the outstanding lip-or ledges 50,51, 52 and 53 respectively. These ledges are cut awayv as at-55 and 57-so-as'to engage the upstanding" rim" lugs it'll and '62 of members 12 and 10. YI hisj arrangementiprovides for the ac-y curate centering and positioning of the jinte'rliner Each of the interliner'members 46 and-43' are provided withfcorresponding halff grooves 68 which when; the" two-halves are placedf together in 1 operating relationship forms excess plaster .discharg eopenings as '70 freely comm nicating with the outside of the flask prop a to further increase the retaining 'ab1l1tyfof. the I interliners for the molded material cast, therein each of the interliner member sfare provided with fluidtplaster. The stone'is imbedded in the same :Inib de anfinwardly extending ledge'as72 and-74.

"In Figure" I"have shown a still' f urther modification whichlmight be taken. as afair represent'ationof either the'upper or lower interliner member which has all the features enumerated and in addition is-slit', preferably, along its minor I axis so that molds can be more easily removed under certain conditions and runner they are.

provided'with inwardly eirtending' fin members as 'lfi'w'hich are so arranged that the molds can be loosened and-pulled otf the cast material: Interlocking securing means should be providedto se-I regulated temperatures. To insure this-uniformity' it is neces'sary w use a thermometerso arranged as to give accurate readings. ':With, this; in mind I "have provided; one" ofy, flask members an'opening as 78 which'is adapted to,

rec eive. a cavity forming plug. This-plug is show'nfmost cl early'iniFigures 4 and 8 as 80 and .is provided with ahandle portion '81',fa reduced size portion83- which rs adapted to-form a'snug r flt in theouter flask member and then'a" reduced' portion;;84fof such afsi z to l1old, in proper position; the closed'en'd thimble 86. I 'When the plug is removed, which will normally'be ,as-so'on' of th.

the cast has set, the tnimbi is 1eft inside so as to provide an accurate and uniform heat trans mitting receiver for the thermometer 88. It is desired to callspecial attention to the relieving of the outer flask and the interlim'ng flask member as shown at 78, and so that the thermometer will not touchany metal excepting the thim- Die 86; The plug should further be of such a size as to provide that 'the cast material itself does not touch theithermometer after the showing of Figure 3. Handle portions 91 and 92 are normally formed as part oithe interliner members'to assist in theeasy handling'of the same. I As an alternate arrangement I have shown a modified securing means for a top plate 16. This consists of a bolt arrangement employing a thru bolt 93 to which is secured an operating handle a 94 which is' arrangedlto' provideoperating means for. slidingfbolt 93' into engagement with post 22 and out of engagement therewith the same heingheld in'the engaged and freed position by a lug 95 arranged toprovide two handle receivthevaricus features may bemore clearly understood let it be assumedthat my flask isbeing used .in producing a false tooth platew assembly; newnormall an impression is made in wax of the oral cavity which is vto. beffitted with a plate, by fiiling the flesh engaging'portion of the impressions thus obtained-with I a hard setting plaster the foundation stone'98 is obtained; This is 'normallyformed with a flat bottom sur-v face' as an added convenience in handling such as is shown in Figure 3. Nowthe upper surface I stone' carries theforin o'f'the oral cavity tli'e'gplate is intended to fit; :The next operation normally is tosecurein place 'on the stone- 98,

by means of low melting wax; the various teeth in -thejir properarrangement; These are indi the lower flask frnember 121with'its interliner '48 "cated at 99 in Figure3; Thenext operation isto i place the stone with the teeth secured thereto into and which has been-previously filled with 'a semi of fluid plaster of Paris, by this is meant plaster of Paris which has been mixed with sufficient Water to wet all the powder particles. Cover'lfi pressing thesame into position assures-that the entire mold is filled, the excess being vforced up and out the various openings 'provided,;such as is then placed in positio'n'as is also the cavity producing plug. 80,'shown in itsproper position: in Figure 4, placing'the cover onthe mold'and 44 and '70. Before'the'pla'ster in the lower half is poured andbefore 'the upperThali is poured upon the lower half some parting medium'should be placed on the lower surface to the-end that the plaster castcan'be parted at'the center of the mold and also easily removed from the lower Before pouring'the' upper half in position it is customary to. normally provide waste grooves or draining channels, in the'slightly hardened 'low- I e'r half, whichfeXtendI outwardly" toopening '70. Assoon asthe-plaster has set the cast is placed in-hot'water and thewax softened so that itwill either drain-I away from the teeth 99-or can be cast material.

easily washed away with hot water when the mold is parted.

The cast with the two interliners surrounding it can now be removed from the flask and placed over any source of dryheat to thoroughly dry the This makes it possible to use one mold proper formed of members 10, 12 and 16 with several sets of interlinersthus affecting a considerable saving due to the fact that the more expensive flask is not tied .up during the drying process. l

After the mold is dried thoroughly and the plaster set firmly the teeth 99 will be held securely in the upper fiask and stone 98 will be secured within the lower portion of the flask. The plate blank is then placed betweenstone 98 and the teeth 99. The flask is reassembled and the whole device placed in a heating press. Naturally as the un-cured blank is considerably too large for the cavity formed previously the two halves of the flask will not meet but as pressure and heat is applied the two halves will gradually force the surplus material out of the central space in the the curing continued with any suitable application of heat.

During the curing operation and while the flask is under the heat press it is necessary that thermometer 88 be installed within the sleeve or thimble 86 after the showing of Figure 3 and the heat supplied during the curing process must be regulated to maintain a temperature, found most satisfactory for the type of material used in the plate blank. In order that accurate reading can be obtained from thermometer 88 it is desirable that the thimble be well within the cavity substantially as indicated in Figure 3 and in the open end of the U formed by the teeth 99. It is then desirable that sufficient clearance be provided for the thermometer so that it will not touch the cast material, the interliner or the outer member 10 as if it did it would'unnecessarily influence the thermometer and inaccurate readings would result. I

During the curing process the dead air space between the outer flask members 10 and 12 and the interliners 46 and 48 provides a heat insulating means which tends to equally distribute the heat and prevent local burning of the denture material.

The foregoing description and the accompanying drawings are believed to clearly disclose .a preferred embodiment of my invention, as used bin dental work, but it will be understood that this disclosure is merely illustrative, that the flask may be used in many fields of'industry and that such changes in the invention may be made as are fairly within the scope and spirit of the following claims:

. Having thus fully described my invention,- what I claim as new and desire to secure by Letters Patent is 1. In a mold'the'combination with a drag section and a cope section, and clamping means therefor, of a separable inner mold comprising a drag section and a cope section, means'for.

the cover for engagement with said pin, a socket member on the drag section for receiving said pin, and a detachable fastening device mounted in the socket member for engagement with said pin.

3. In 'a dental mold the combination with a drag section, a cope section and a removable cover having a socket member rigid therewith, of a centering pin threaded in a part of the cope section, a portion of said pin extending in said socket member and a 'set screw in said member for engagement with the pin, a socket member on the drag section, and a spring-pressed latch-bolt socket member for enmounted in the second gagement with. said pin.

4. In a dental mold the combination with a drag section, a cope section, and a removable ice cover having an exterior socket member, of socket member on the drag section and cope section l adapted for alinement with the first socket memvber, a centering pin having an intermediate threaded portion engaging the socket member of the cope section, a set screw mounted in the socket member of the cover for engaging said pin, an angular spring-pressed, rotatable and slidable bolt mounted in the socket member .of--

the drag section for engagement with the pin,

and a cam device for co-action withsaid ,bolt in withdrawing the bolt from the pin.

5. In a dental mold the combination with a drag section, a cope section, a removable cover,

and clamping means for said members, of a removable recess-forming plug adapted to be in-' serted through a lateral opening in the cope section, and a separable ferrule on the inner end of said plug, 'whereby said plug may be withdrawn leavingthe ferrule fixed in the wax core.

6. In a mold the combination with a drag section and a cope section, and clamping means therefor, of a separable inner mold comprising a drag section and a cope section, means for spacing these inner sections Within the mold, means for retaining the inner mold within the outer mold, a removable recess-forming plug inserted through alined lateral openings in the 'inner and outercope sections, and a separable ferrule on the inner end of said plug, whereby fixed in the wax core of the mold.

CHARLES S. BALLARD.

said plug may be withdrawn leaving the ferrule 

